Thread grinding machine



March 24, 1942. w, DALZEN 1 2,277,213

THREAD GRINDING MACHINE Filed April 19, 1941 6 Sheets-Sheet 1 INVENTOR.

prr mvry March 24, 1942. w. F. DALZEN 2,277,213

THREAD GRINDING MACHINE Filed April 19, 1941 6 Sheets-Sheet 2 INVENTOR,BY Wm March 24, 1942. w. F. DALZEN 2,277,213

THREAD GRINDING MACHINE Filed April 19, 1941 6 Sheets-Sheet 3 INVENTOR.

HTTOENE) March"24, 1942. w. F. DALZEN 2,277,213

THREAD GRINDING MACHINE Filed April 19, 1941 6 Sheets-Sheet 4 March 24,1942.

w. F. DALZEN 2,277,213

THREAD GRINDING MACHINE Filed April 19,- 1941 e sheetg-sheet s FiledApril 19, 1941 6 Sheets-Sheet 6 ?aienied Mar. 24, 1%42 I ES 27 Claims.

This invention relates to cutting and grinding machines and moreparticularly to thread grinding machines.

Hertofore devices of this type have been com plicated by unnecessarymachinery and working parts whereby said machines have been diilicultand expensive to manufacture.

Due to the largeness and complicated nature of machines of this type thecost of maintenance has been higher and the accuracy thereof has beenreduced due to wear on more workingparts. It is therefore the object ofthis invention to provide a thread grinding machine which dueto itssimplicity is far more accurate than machines of this type heretoforeconstructed.

It is the object of this invention to provide a thread grinding machineof simple construction having a minimum number of parts, built atconsiderably less expense than heretofore expended for machines of thistype.

It is the further object hereof to provide a thread grinding machinewith a maximum production capacity in excess of similar machines of thistype.

It is the further object of this invention to provide in a threadgrinding machine and in combination therewith a novel grinding wheelform dresser adapted to produce various shaped surfaces in the edge ofthe abrasive grinding wheel for accurately grinding out various shapesof threads. Y

It is the further object hereof to provide in said dressing mechanism anauxiliary dressing attachment for producing a curved surface upon theouter peripheral edge of the abrasive grinding wheel.

It is the still further object herein to provide a simple cam attachmentfor said machine whereby radial relief may be obtained in making taps,reamers, or similar tools, or other articles be reproduced in the workif desired.

It is the still further object hereof to provide means for supporting-arotatable grinding wheel above the work, together with means for raisingwhere it is desired to vary the radial diameter at certaincircumferentially spaced points upon a cut or ground surface.

It is the still further object of this invention to provide a novel runout slide whereby at the end of the threads and on the last thread, thework is gradually dropped away from the cutting wheel, giving a gradualrun out from the root diameter of the thread to the extreme outsidediameter of the part.

It is the still further object of this invention to provide a carriagesupporting slide mechanism which may be angularly adjusted with respectto the horizontal for producing a taper in the work supported by saidcarriage. On the other hand,

and lowering said wheel with respect thereto.

It is the still further object herein to provide a vertically adjustabletail stock for supporting a rotatable work whereby a taper in eitherdirection may be cut or ground thereon.

It is the still further object hereof to provide compensating means forraising and lowering the grinding wheel support and also the dresserwith a proportional movement of the latter with re spect to saidsupport.

Other objects will be seen in the various arrangements of parts andcombinations thereof as will be hereinafter described in connection withthe appended drawings of which:

Figure 1 is a side elevational view of the thread grinding machine.

Figure 2 is a front elevational view of the same.

Figure 3 is a top plan view thereof.

Figure 4 is a side elevational view on the end opposite to that ofFigure 1. I

Figure 5 is a fragmentary plan view showing the transmission andreversing mechanism.

Figure 6 is a fragmentary elevational view of the carriage, and supporttherefor.

Figure 7 is a fragmentary elevational view of the rocker, cam, carriage,and reversing mechanism.

The above drawings illustrate merely preferable embodiments of theinvention, it being expressly understood that it is not intended thatthe invention be limited thereby.

In the drawings, a grinding wheel dresser is generally indicated as Awith its housing H vertically and reciprocably mounted within thesupport l2 with friction minimizing ball races or ways 43 interposedtherebetween. Support lZ is joined to the vertically movable grindingwheel support or housing I4 and is adapted to move therewith.

Hand wheel i5 operating through gears l6 and I1 turns the threaded shaftor screw l8 which. supported bycolumn l9, raises and lowers housing Iand the abrasive grinding wheel 20 with respect to said column. Thewheel dresser A and housing H are also raised and lowered by hand wheell5 operating through the movable wheel support. It will be noted thatwheel 20 may be a metal cutter where it would be desirable for cuttingsofter metals than that of which the cutter consists.

Lever 2| has a lug on its end adapted to support the housing I! of thedressing mechanism A. Said housing while resting upon the end of lever2| is longitudinally and reciprocably journaled within the verticalsupport l2.

Said lever 2| is centrally pivoted at point 23 to the movable housing Hwhich provides a movable the column l9. A washer is secured upon theendof screw 2| by a nut 23'; and'the end of lever 2| is beneath saidwasher. whereby a retaining means is provided preventing rotation oflever 2|.

A calibrated bolt H is threadably disposed on the lower end of thecompensating screw 2| and thereby provides a manually operable adjustingmeans permitting longitudinal adjustment of the compensating screw 2|whereby the lever 2| is correspondingly adjusted as desired.

Housing |4 slides relatively to column IS with the dovetail 24, and ashas been described, is adjustable with respect thereto bythehandwheell5.

The wheel dressing mechanism is claimed in my divisional applicationSerial No. 423,517, filed December 18, 1941.

As seen in Figure 3 column 19 is angularly' adjustable upon the upperbed upon the arcuate T slots 26, with securing bolts 21 positionedthrough the lower portion of column 9 with the heads thereof slidablydisposed within said T slots. By virtue of this arrangement the grindingwheel 28 may be angularly disposed to the desired angle of lead withrespect to the work supported therebeneath in the manner hereinafterdescribed.

In applicant's preferable embodiment, said 001- umn is adapted forarcuate adjustment through an arc of 45 degrees, which may bedistributed proportionately on either side of center.

Bed 25 also longitudinally adjustable upon the base 28 is slidable withrespect thereto by means of the T slots 29 therein. A threaded squareheaded shaft 30 is preferably employed for manually moving, by asuitable means, bed 25 with respect to said base member.

A basin or edging 3| is horizontally disposed upon the base member 28for retaining the cooling oil after it has flowed from the work, whenceit is conducted back to the fluid sump 32 within the base member 28.

A centrifugal pump 33 supported by said base member is in communicationwith the coolant sump 32, and is adapted to supply coolant through asuitable conduit to the point of engagement of the grinding wheel andwork. From this point cooling fluid such as oil or other suitablecomposition descends to the basin 3| whence it returns to the sump 32.

As shown in Figure l, a removable shield or splash guard 34 is providedremovably secured 2,277,213 to the front portion 'of basin 3| by clips35 for protecting the operator from splashing oil.

A motor 36 is supported within column l9 and is joined to the grindingwheel spindle 31 by any suitable belting 38 or other connecting meanswith suitable means such as step pulleys employed for varying the speedof said spindle.

Another 'motor 39 is supported within base member 28 with a plurality ofstep pulleys 40 joined thereto for operable engagement selectivelythrough belt 4| with a plurality of step pulleys 42 upon an idler 43which in turn is joined by suitable pulleys 44 and 44' and a belt 45 forrotating sleeve 46 within a suitable bearing support 41. By' virtue ofsaid pulleys a plurality 'of speeds for said sleeve may be obtained whendesired. However, it will be noted that other variable means may beemployed for connecting motor 39 with rotatable sleeve 46. Sleeve 46opcrates drive shaft 48 with a speed-up transmission 49 interposedtherebetween, said shaft being disposed concentrically within saidsleeve.

Referring to Figures 1 and 5 a gear 58 secured upon sleeve 46 androtatable therewith has on its outside edge a clutch member 5|. Shaft 48has a gear 52 thereon rotatable therewith but adapted for a reciprocablesliding movement thereon over splines 53 in said shaft. The outsidesurface of gear 52'a1so has a clutch member 54 adapted for cooperatingengagement with clutch member 5| when gear 52 is moved to the left inthe manner hereinafter described. So moved, it is seen that sleeve 46and drive shaft 48 move together with no speed up.

A speed-up gear 55 on shaft 56 is in mesh with gear 50 for operatinggear 51, on the other end of said shaft. With gear 52 moved to the rightit is in engagement with gear 51 whereby a speedup is obtained betweensleeve 46 and drive shaft 48.

The means employed for longitudinally sliding gear 52 upon drive shaft48 consists of a bifurcated stirrup or forked member 58 adapted toloosely engage the edges of gear 52 for sliding the same upon shaft 48for engagement and disengagement of clutch members 5| and 54.

Forked member 58 is secured on the end of a manually actuated shaft 59providing operative control for the above described transmission. In oneposition of gear 52 as at the left the connection between sleeve 46 andshaft 48 is direct. With gear 52 moved to the right by shaft 59 sleeve46 is indirectly joined to shaft 48 throughthe speed-up transmissiongears 50, 55, 51 and 52.

' Gear 68 on the end of drive shaft 48 is in engagement with gear 6|,with the latter loosely journaled upon shaft 62 and rotatableindependently thereof. A reverse gear 63 in spaced Y relation to gear 6|is also loosely journaled around shaft 62 and movable independentlythereof, but meshing with gear 69.

A clutch member 64 is slidably disposed upon shaft 62, movable therewithbut adapted to positions of engagement with either gear 6| or gear 63 orin aneutral position therebetween.

Said clutch64 is therefore adapted to turn with either gear 6| or 63whereby shaft 62 is turned in one direction or the reverse thereof.

The position of clutch 64 upon shaft 62 is regulated by a manuallyactuated latch or handle 65 disposed in the front of the thread grindingmachine and adapted for movement to the left and to the right.

A-shaft 66 is joined to said handle and has on its end a gear 61 whichis in mesh with a similar gear 68' for turning another shaft 69. A gearI8 is on the end of shaft 69 and cooperatively engages clutch 84 bymeans of a rack gear II thereon. I

Consequently movement of handle 85 causes a corresponding movement ofclutch 64 for disengaging drive shaft 82 from drive shaft 48, and forregulating the movement of said drive shaft 62 in one direction or theother. This manual control also regulates the reciprocable movement ofthe work supporting spindle and also the rotatory movement of the workwith respect to the grinding wheel 20. Y

Referring-to Figures -9 and 7 it is seen that the manual control 85 hasa roller member 86" adapted to be engaged by the vertically disposedstops 61' secured to the reciprocable work support carriage 68. It willbe noted that these stops 61' are adapted to longitudinal adjustment andare secured to themovable carriage by suitable securing means 69'.

In operation, with said carriage moving in one direction, when one ofsaid stops engages the roller 68' on the handle 65 said handle is turnedto a neutral position which automatically disengages the drive shaft 62by means of the clutch mechanism 84 hereinbefore described.

Shaft 62 has near its end a gear I2 in mesh with gear I3 for providingrotative motion of the lead screws I4 to which it is attached. Theopposite end of said lead screw'is supported by a longitudinallyadjustable tailstock I50 thereby permitting the use of different lengthsof lead screws if required.

It will be noted that the lead screw is adapted to cause reciprocablemovement of a work supporting carriage 68 with respect to the rotativegrinding wheel 28, and is also adapted to cause rotation of the workitself in the manner hereinafter described.

A suitable nut I5, wedged up against the under side of thereciprocable-carriage 68 by means of a manually actuated eccentric pinI5',threadably engages said lead screw I4 causing reciprocable slidingmovement of carriage 68 with the direction thereof governed by thedirection of movement of said lead screw. It is seen that merely byturning the eccentric pin I5 that nut I5 carrying lead screw I4 issecurely locked in place. More particularly a lug I50 downwardly dependsat right angles from the carriage 88, and has a longitudinal slot I5 Itherethrough. The nut I5 for the lead screw I4 is adapted to have itsbottom portion snugly disposed within slot iii. A stop plate I52 issuitably secured, to lug I50 on one side of slot I5I adjacentoneedge ofnut I5 limiting movement thereof with respect to lug I50 and carriage68.

The eccentric pin I5 engages the opposite edge of nut I5 ,wedging thesame, when operative, against the stop plate I52. Thus the nut I5,maintained securely against the underside of carriage 68 by lug I58 andeccentric pin I5 is adapted to reciprocably actuate said carriage uponrotation in one direction or the other of lead screw 14. It will benoted that suitable means are employed as hereinabove described wherebythe direction of motion thereof is manually or automatically reversed ordisengaged.

Reversal of the direction of movement of lead screw I4 in turn resultsin reversal of the longitudinal movement of the work supporting carriage68 and at the same time reversal of the direction of rotative movementof the work.

Gear I3 is also in mesh with gear I4 for tumcenter 18'. It will beunderstood that said sleeve and center are removable to permit theJournaling of a long piece of work concentrically within the hollowspindle I8 if necessary. Other suitable work securing means may then beemployed for retaining and supporting the work.

Longitudinal movement of the work supporting carriage 88 coincides withthe rotary movement of the work supporting spindle It in one directionby means of the intermeshing gears I3 and .It may. be desirable,however, that for such movement of the carriage 68 that the work rotatein the opposite direction. To accomplish this a removable idler gear I3supported by a suitable bracket 13" is in mesh with gear I3.

A manually actuated gear shifting fork I4" is adapted to engage theannularly recessed gear shifting means II which is secured to thespindle driving gear 14'. Movement of fork 14" causes gear I4 to movelongitudinally upon spindle I6 on a suitable keyway or splines bringingsaid gear into mesh with the idler gear I3. So connected, the rotarymotion of spindle I6 is thereby reversed independently of the work.carriage 68, and without changing the lead screw.

In this connection a tail stock I8 is also employed for supporting thework at its opposite end. Said tail stock adjustable horizontally upon akeyway I8 on the carriage, 68 for different lengths of work, is alsoadjustable vertically by suitable means, as for instance, a screw with adovetail connection between said tall stock and support.v Thereby withvertical adjustment of said tail stock a taper in either direction maybe put upon the work if desired.

Referring again to work carriage 68, as in Figures 1 and 7 it is seenthat the same is angularly' supported with respect to the sub-table 8|.By interposing ball races or ways 82 along the entire engaging surfacesof said sub-table and work siipporting carriage, friction therebetweenis minimized providing a free acting reciprocable movement for thelatter.

Sub-table 8| pivotally secured to the lever atpoints 83 is angularlydisposed and pivotally supported at its upper edge by hinge members 84with the bearings 85 therefore loosely disposed around the shaft 62, andsupported by the drive shaft bearings 86 which are in turn supported inthe base 28 of the thread grinding machine. Thus it isseen that thesub-table 8I is pivotally supported about the axis of the drive shaft 62as shown in Figures 8 and 10.

Gear 81 is joined to shaft 62 adapted to mesh with another gear 88 foroperating a cam shaft 89. Cam 90 secured upon the end of said shaft isadapted to produce a reciprocable rocking movement of the sub-table 8|.This movement is employed wherever it is desired to obtain radial reliefin the grinding of taps, reamers, or

similar tools. In other words, by this device the thread channel put ona tap or other tool may have a variable radius at certaincircumferentially spaced points.

The cam- 90 is adapted to engage the upper surface of a lever 80 at oneend thereof. A fulcrum 9| is provisioned beneath lever 80, and issupporting carriage 68 on which is disposed the.

work support 16, and also the tail stock I8.

Fulcrum Si is slidably adjustable with respect to a calibrated scale 92under the lever whereby different degrees of movement are obtained forthe sub-table 8|. It will be noted that the cam shaft 89 is adapted fordisengagement with gear 88 whenever its use is not required.

A run-out slide mechanism is herein provided whereby at the end of thethreads and on the last thread the work carriage 68 and sub-table 8i andthe work are gradually dropped away from the cutting wheel, giving agradual runout of the thread'channel from the root diameter of thethread to the extreme outside diameter of the work.

This eliminates the abrupt stoppage of the thread as has been the caseheretofore. This point of stoppage has been a bending point between thethreaded portion and the body portion, and as a result when breakageoccurred, it oocurred in this point. By eliminating this abrupt stoppageof the thread and running the same out gradually to the extreme diameterof the part, bending is distributed over a greater length of the work.

The run-out slide mechanism as illustrated in Figure 2 consists of alongitudinally disposed supporting member 93 adjustably secured on thefront of the base member 28 at points 94 with one end of said supportangularly cut away as at 95. Guide means 96 depending downwardly fromthe reciprocable carriage 68 cooperatively register with the top surfaceof the supporting slide member 93 and support said carriage with respectthereto.

It will be noted that by adjustment of securing means such as screws atpoints 94, member 93 may be angularly disposed with respect to thehorizontal. By so doing a gradual taper may be obtained throughout thelength of the work if desired.

On the other hand member 93 may have an irregularly -shaped uppersurface upon which guide 96 will register. shaped surfaces may bereproduced in the work supported by the movable carriage 68.

. It will be noted further in this connection that when grinding taps orreamers employing the use of the cam attachment 9!], heretoforedescribed, that the run-out slide mechanism is disengaged.

- On the other hand when using the run-out slide 93 and support 96 thecam attachment 90' is disconnected.

As the work and table are moved to the right with the wheel 20 ingrinding engagement with the rotated work, the guide 96 follows'the topsurface of the slide 93. When said guide reaches the inclined portion 95it is seen that the work support 68 is gradually dropped away from thegrinding wheel 29 which results in a gradual run-out of the threads cutfrom the root diameter to the outside diameter of the work.

In grinding out threads upon a rotated work piece it will be seen thatthe .size and number of Consequently irregularly threads per inch varieswith each job. Consequently the correct pitch is obtained by making thelead screw 14 and nut 15 readily removable and interchangeable withothers of different pitches. Therefore it is seen that the threadgrinding device described herein has a multiplicity of uses and itsversatility and adaptability to various types of jobs is apparent;

It will be noted from the above description that the thread grindingmechanism provides driving means for reciprocating the work supportingcarriage 69 in the form of a lead screw M and also atthe same timeprovides intermeshing means 13 and M for rotating the work throughoutreciprocable movement thereof.

From time to time the grinding wheel 20 becomes worn requiring adressing operation; or on the other hand it may be desired to vary theform of the cutting edge thereof for providing a particular shape ofthread.

For these purposes a wheel dresser A is employed having a housing I!vertically and recipcarriage supported upon said base, a work supportingand rotating spindle upon said carriage with an operating gear joined tosaid spindle, a reversible power shaft having a gear thereon, arotatable lead screw in threaded engagement with said carriage, andhaving a gear joined thereto intermeshing with said power shaft gear andsaid spindle operating gear.

- 2. In a thread grinding machine the combination, a base, areciprocable work supporting and rotating carriage disposed thereon, avertically adjustable support on said base, a rotatable thread grindingwheel carried by said support, a wheel dresser adjustably carried bysaid support, and means pivoted to said support with said dresser ridingupon one end thereof and the other end adjustably secured to said base,whereby movement of said support causes a correspondlng proportionalmovement of said dresser.

3. In a thread grinding machine having a carriage support, alongitudinally reciprocable carriage slidably mounted upon said supportwith a spindle thereon for rotatably supporting a workpiece, and alsohaving a rotatable grinding wheel adjustably supported adjacent saidworkpiece; a drive shaft, a cam operable from said drive shaft, a leverpivoted on one end to said carriage support, and cooperatively engagingsaid cam on its other end, and a fulcrum intermediate the ends of saidlever, whereby an intermittent radial motion of said carriage supportrelative to said grinding wheel is imparted.

4. In a thread grinding machine having a pivotal carriage support, alongitudinally reciprocable carriage slidably mounted upon said supportwith a spindle thereon for rotatably supporting a workpiece, and alsohaving a rotatable grinding wheel adjustably supported adjacent saidwork-piece; a drive shaft, a cam operable from said drive shaft, a leverpivoted on one end to said carriage support, and cooperatively engagingsaid cam on its other end, and a fulcrum intermediate the ends of saidlever, whereby an intermittent radial motion of said carriage supportrelative to said grinding wheel is imparted, said fulcrum beinglongitudinally adjustable with respect to said lever forregulating thedegree of said radial motion.

5. In a thread grinding machine having a base member and a drive shaftjoumaled therein and also a grinding wheel; a carriage support pivotallyhinged upon its upper edge to said drive shaft, a reciprocable carriageupon said support with a spindle thereon for rotatably supporting awork, and a rotatable cam actuated by said drive shaft and engageablewith said carriage support for intermittently imparting a radial motionthereto around said drive shaft axis, relative to said grinding wheel.

6. A thread grinding machine comprised of base, a slide longitudinallyadjustable thereon, an angularly adjustable column upon said slide, ahousing longitudinally adjustable upon said column, a grinding wheeljoumaled thereby, a longitudinally reciprocable carriage supported uponsaid base, a work supporting and rotating spindle upon said carriage, agrinding wheel dressing'mechanism slidably disposed upon said housing,and compensating means pivoted to saidliousing with one end adjustablysecured to said column and the other end supporting said dressermechanism, whereby upon adjustment of said housing a proportionaladjustment is obtained between said dressing mechanism and said grindingwheel.

7. A thread grinding machine comprised of a base, an angularlyadjustable column upon said base, a housing longitudinally adjustableupon said column, a grinding wheel joumaled thereby, a grinding wheeldressing mechanism slidably and vertically disposed upon said housingabove said grinding wheel, and compensating means pivotally mounted onsaid housing with one end adjustably secured to said column, and itsother end providing a support for said dressing mechanism, whereby uponfeeding adjustment of'said housing, said dresser is permitted to descendby its own weight for obtaining a proportional adjustment between saiddresser and said grinding wheel.

8. A thread grinding machine comprised of a base, an angularly disposedsub-table pivotally mounted along one of its longitudinal edges abovesaid "base, a longitudinally reciprocable work supporting and rotatingcarriage upon said subtable, a rotatable grinding wheel adjustablysupported above said carriage, an irregularly shaped slide memberadjustably secured to said base, a guide member depending from saidcarriage for supporting the same upon said slide, whereby the carriagethroughout longitudinal movement is adapted to be pivoted about thelongitudinal edge of said sub-table for transverse movement relative tosaid grinding wheel, following the contour of said slide member.

9. In a thread grinding machine having a base, a rotatable grindingwheel adjustably supported on said base, and a drive shaft; an angularlydisposed carriage support pivotally journaled upon its upper edge tosaid drive shaft, a longitudinally reciprocable workpiece supporting andlarly shaped slide member adjustably secured to said base, a guidemember depending from said carriage for supporting the same uponsaidslide,

trolling the movement of said carriage and said spindle, an angularlydisposed carriage support pivotally hinged along its longitudinal edgeto said drive shaft, and a speed-up transmission between said'powershaft and said drive shaft Y for manually regulating the speed of thelatter.

11. In a thread grinding machine having a longitudinally reciprocablecarriage with a spindle therein for rotatably supporting a workpiece,and also having a rotatable grinding wheel adjustably supported abovesaid work; a drive shaft, a rotatable lead screw operated by said shaftfor actuating said carriage, an angularly disposed carriage supportpivotally and hingedly secured along one of its longitudinal edges tosaid power shaft, means interconnecting said spindle with said-leadscrew, a reversing idler interconnected with said lead screw, andmanually actuated means for interconnecting said reversing idler withsaid spindle, whereby the direction of rotation of the work is reversedwithout effecting the direction of feed of the carriage. p

12. In a thread grinding machine having a base, an adjustable grindingwheel, and a power shaft; an angularly disposed. carriage supportpivotally and hingedly joumaled along one of its longitudinal edges tosaid power shaft, a longitudinally reciprocable work rotating andsupporting carriage mounted upon said support, and a plurality offriction minimizingmeans interposed between said carriage and saidsupport.

13. In a thread grinding machine having a drive shaft and an angularlydisposed carriage support pivoted along its longitudinal edge to saiddrive shaft, a longitudinally reciprocable carriage with a spindlethereon for rotatably supporting a workpiece, and also having arotatable grinding wheel adjustably supported adjacent said work; adrive shaft, a cam shaft operable from said drive shaft, a cam on saidcam shaft, a lever pivoted on one end to said carriage support, andcooperatively engaging said cam on its other end, and a fulcrumintermediate the ends of said lever, whereby an intermittent radialmotion of said carriage support about said drive shaft relative to saidgrinding wheel is imparted.

14. In a thread grinding machine having a drive shaft and an angularlydisposed carriage support pivoted to said shaft; a longitudinallyreciprocable carriage with a spindle thereon for rotatably supporting aworkpiece, and also .having a rotatable grinding wheel adjustablysupported adjacent said work; a drive shaft, a cam operable from saiddrive shaft, a lever pivoted on one end to said carriage support, andcoopera fulcrum intermediate the ends of said lever,

ro ating carriage upon said support, an irregu.. whereby an intermittentradial motion of said carriage support about said drive shaft relativeto said grinding wheel is imparted, said fulcrum being longitudinallyadjustable with respect to said lever for regulating the degree of saidradial motion.

15. A thread grinding machine comprised of a base, an angularlyadjustable column thereon, a rotatable grinding wheel adjustablysupported upon said column, a longitudinally reciprocable carriagesupported upon said base, a work supporting and rotating spindle uponsaid carriage, with an operating gear joined to said spindle, areversible power shaft having a gear thereon, a rotatable lead screw inthreaded engagement with said carriage, and having a gear joined theretointermeshing with said power shaft gear and said spindle operating gear,a reversing idler interconnected with said lead screw, and manuallyactuated means for interconnecting said reversing idler with saidspindle whereby the direction of rotationof the work is reversed withouteffecting the direction of feed of the carriage.

16. In a thread grinding machine having a base and an adjustablegrinding wheel; a carriage support upon said base, a longitudinallyreciprocable work rotating and supporting carriage slidably mounted uponsaid support, and having depending therefrom a recessed shoulder, andinteriorly threaded nut, removably disposed within said recess, a stopplate secured to on said column, a reciprocable carriage upon.

said base; ,a work supporting and rotating spindle upon said carriage,with an operating gageable cam operable from said drive shaft, a leverpivoted on. one end to said carriage support, and cooperatively engag gsaid cam on its other end, and a fulcrum intermediate the ends of saidlever, whereby an intermittent radial motion of said carriage supportrelative to' said grinding wheel is imparted.

. 20. In a thread grinding machine having a pivotal carriage support, alongitudinally reciprocable carriage slidably mounted upon said supportwith a spindle thereon for rotatably supporting a work-piece, and alsohaving a rotatable grinding wheel adiustably supported adjacent saidwork-piece; a drive shaft, a cam operable from said drive shaft, a leverpivoted on one end to said carriage support, and cooperatively engagingsaid cam on its other end, a fulcrum intermediate the ends of saidlever, whereby an inter- 'mittent radialxmotion of said carriage supportrelative to said grinding wheel is imparted, said fulcrum beinglongitudinally adjustable with respect to said lever for regulating thedegree of said radialmotion, and calibrated means adjacent said fulcrumfor predetermining the position thereof.

21. In a thread grinding machine having a base member and a drive shaftjoumaled therein and also a grinding'wheel; a carriage support pivotallyhinged to said drive shaft, a reciprocable carriage upon said supportwith a spindle thereon for rotatably'supporting a work-piece, and arotatable cam engageable with said carriage support for intermittentlyimparting a radial motion thereto around said drive shaft axis, relativeto said grinding wheel.

22. In athread'grinding'machine having a longitudinally reciprocablecarriage with a spindle thereon for rotatably supporting a work-piece,and also having a rotatable grinding wheel adgear joined to saidspindle, a reversible power shaft having a gear thereon, a rotatablelead screw in threaded engagement with said carriage, and having a gearjoined thereto inter-meshing with said-power shaft gear and said spindleoperating gear.

18. In a thread grinding machine the combination, a base, a reciprocablework supporting and rotating carriage disposed thereon, a column uponsaid base, a vertically adjustable support upon said column, a rotatablethread grinding wheel carried by said support, a wheel dresseradjustably carried by said support, and means pivoted to said supportwith said dresser riding upon one end thereof and the other endadjust--- ably secured to said column, whereby movement of said supportcauses a corresponding proportional movement of said dresser.

19. In athread grinding machine having a carriage support, alongitudinally reciprocable justably supported above said work-piece; adrive shaft, a rotatable lead screw operated by said shaft for actuatingsaid-carriage, an angularly disposed carriage support pivotally andhingedly secured to said power shaft, means interconnecting said spindlewith said lead screw, a reversing idler interconnected with said leadscrew, and manually actuated means for interconnecting said reversingidler with said spindle, whereby the direction of rotation'of thework-piece is reversed without effecting the direction of feed ofcarriage slidably mounted upon said support with -a spindle thereon forrotatably supporting a work-piece, an operating gear joined to saidspindie, and also having a rotatable grinding wheel adjustably supportedadjacent said work-piece; a reversible drive shaft with a plurality ofgears thereon, a rotatable lead screw in threaded engagement with saidcarriage, and having a gear joined thereto intermeshing with said powershaft gear and said spindle operating gear, a disenthe carriage.

23. In a thread grinding machine having a base, an adjustable grindingwheel, and a power shaft; an angularly disposed carriage supportpivotally and hingedly joumaled to said power shaft, a longitudinallyreciprocable work rotating and supporting carriage mounted upon saidsupport, and a plurality of friction minimizing means interposed betweensaid carriage and said support.

24. In a thread grinding machine having a base, an adjustable grindingwheel, and a power shaft; an angularly disposed carriage supportpivotally and hingedly journaled to said power shaft, and a,longitudinally reciprocable work rotating and supporting carriagemounted upon said support.

25. In a thread grinding machine having a base, an adjustable grindingwheel, and a power shaft; an angularly disposed carriage supportpivotally and hingedly-joumaled to said power shaft, a longitudinallyreciprocable work rotating and supporting carriage mounted upon saidsupport, and manually operable means for reversing the direction ofrotation of said power shaft.

26. In a thread grinding machine having a base, an adjustable grindingwheel, and a power shaft; an angularly disposed carriage supportpivotally and hingedly journaled to said power shaft, a longitudinallyreciprocable work-piece rotating and supporting carriage slidablymounted upon said support, manually operable means for reversing thedirection of movement of said carriage, andmeans in spaced relationsecured to said carriage for actuating said manually operable reversingmeans to automatically disen- 10 ing said power shaft.

WILLIAM F. DALZEN.

